tion that goes to completion (this is not a reversible reaction) what happens to the rate with the addition of a catalyst?  Will the rate increase, decrease, or stay the same?

By which of the following mechanisms does a catalyst operate? a. It decreases the activation energy barrier for a reaction. b. It serves as a reactant and is consumed. c. It increases the temperature of a reaction. d. It increases the concentration of reactants.

. Consider the exothermic reaction CO(g)+2H2(g)CH3OH(l)Predict three changes that could be made to the system that would decrease the yield of product over that produced by a system in which no change was made.

Classify each of the following statements as true or false. aSome equilibria depend on a steady supply of a reactant in order to maintain the equilibrium. bBoth forward and reverse reactions continue after equilibrium is reached. cEvery time reactant molecules collide, there is a reaction. dPotential energy during a collision is greater than potential energy before or after the collision. eThe properties of a transition state are between those of the reactants and products. fActivation energy is positive for both the forward and reverse reactions. gKinetic energy is changed to potential energy during a collision. hAn increase in temperature speeds the forward reaction but slows the reverse reaction. iA catalyst changes the steps by which a reaction is completed. jAn increase in concentration of a substance on the right-hand side of an equation speeds the reverse reaction rate. kAn increase in the concentration of a substance in an equilibrium increases the reaction rate in which the substance is a product. lReducing the volume of a gaseous equilibrium shifts the equilibrium in the direction of fewer gaseous molecules. mRaising temperature results in a shift in the forward direction of an endothermic equilibrium. nThe value of an equilibrium constant depends on temperature. oA large K indicates that an equilibrium is favored in the reverse direction.

The equilibrium constant expression for a given reaction depends on how the equilibrium equation is written. Explain the meaning of that statement. You may, if you wish, use the equilibrium equation N2(g)+3H2(g)2NH3(g) to illustrate your explanation.

When writing an equation, how is a reversible reaction distinguished from a nonreversible reaction?

. Explain what it means that a reaction has reached a state of chemical equilibrium. Explain why equilibrium is a dynamic state: Does a reaction really “stop” when the system reaches a state of equilibrium? Explain why, once a chemical system has reached equilibrium, the concentrations of all reactants remain constant with time. Why does this constancy of concentration not contradict our picture of equilibrium as being dynamic? What happens to the rates of the forward and reverse reactions as a system proceeds to equilibrium from a starting point where only reactants are present?

Substances that poison a catalyst pose a major concern for many engineering designs, including those for catalytic converters. One design option is to add materials that react with potential poisons before they reach the catalyst. Among the commonly encountered catalyst poisons are silicon and phosphorus, which typically form phosphate or silicate ions in the oxidizing environment of an engine. Group 2 elements are added to the catalyst to react with these contaminants before they reach the working portion of the catalytic converter. If estimates show that a catalytic converter will be exposed to 625 g of silicon during its lifetime, what mass of beryllium would need to be included in the design?

For each of the changes listed will the rate of the following chemical reaction increase, decrease, or remain the same? Fe(s)+2HCl(aq)FeCl2(aq)+H2(g) a. the concentration of HCl is decreased b. the iron is ground into a powder c. a catalyst is added to the reaction mixture d. the temperature of the solution is decreased